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PubMed2001

Rheological behavior of Phanerochaete chrysosporium broth during lignin degradation.

Rheological behavior of a lignin-degrading culture of Phanerochaete chrysosporium CDBB-H-298 was determined. Rheological characteristics revealed a Newtonian behavior in the culture medium without fungi, and a non-Newtonian dilatant behavior with fungi. In addition, the rheological behavior of the lignin-containing culture medium was complex, and changed from dilatant to pseudoplastic. During fungal growth without lignin in Kirk media rheological behavior exhibited a parabolic profile, and thixotropy showed a tendency to increase. Results indicated a small increase in the apparent viscosity in the presence of lignin; however, this may not affect the oxygen and mass transfer coefficients. The present findings can be applied to bioreactor desing for waste water treatment.

Biodegradation, Environmental↗
PubMed1978

The lignin fraction of plant cell walls.

Methods are discussed for determining lignin in plant cell walls. The increase in apparent lignin content that may occur as a result of artifacts produced during food preparation is also discussed. The phenolic components, including lignin, of cell walls separated from 12 vegetable, fruit, and cereal foods are determined. Wheat bran, on a fresh weight basis, had a high cell wall content (48.6%) compared with the vegetables and fruit whose contents ranged from 1.0 to 6.0%. Wheat bran and spinach cell walls had the highest lignin contents (11.4 and 4.4%, respectively) and the lowest degradabilities (35.8 and 39.6%, respectively) as determined by a cellulase technique. Cell walls of spinach, beetroot, sweet corn, pineapple, and wheat bran contained the phenolic acids (ferulic, p-coumaric, and diferulic) bound to polysaccharide components. Cell walls of cabbage, Brussels sprout, celery, cauliflower, green bean, carrot, and pea contained only traces of these acids.

Cell Wall↗
PubMed1996

Alterations in the biosynthesis of lignin in transgenic plants with chimeric genes for 4-coumarate: coenzyme A ligase.

The introduction of chimeric sense and antisense gene constructs for 4-coumarate:coenzyme A ligase into tobacco plants caused the reduction of the 4CL activity in the transgenic plants. In the transgenic plants, the cell walls of the xylem tissue in stems were brown and the molecular structure of lignin in the colored cell walls was dramatically different from that in the control plants. Analysis with different types of stain revealed that levels of cinnamyl aldehyde residues and syringyl units in lignin were depressed in the brownish cell walls. Furthermore, the lignin content in colored tissue was lower than that in the normal tissue. Our results indicate that 4CL has important roles in the determination of the composition and the amount of lignin in tobacco plants.

Blotting, Northern↗
PubMed1993

In situ localization of the secretion of lignin peroxidases in colonies of Phanerochaete chrysosporium using a sandwiched mode of culture.

Protein secretion and growth were investigated in Phanerochaete chrysosporium by using cultures sandwiched between perforated polycarbonate membranes. Labelling of colonies with radioactive N-acetylglucosamine and L-methionine indicated a close correlation between growth and general protein secretion, even in a central area of the colony secreting the idiophase enzymes lignin peroxidase (LiP) and manganese-dependent lignin peroxidase (MnP). Comparison of the sites of release into the medium of newly synthesized proteins and immuno-detected lignin peroxidases suggested that diffusion of the enzymes from the walls was a limiting step in the release of peroxidases into the medium. Microautoradiography of colonies exposed to N-acetyl[3H]glucosamine revealed the apical growth of thin hyphae and branches (4 to 5 microns diameter on average) in the central secreting area. These secondary hyphae showed peroxidase activity and reacted with lignin peroxidase antibodies. Although it was not possible to directly visualize secretion at hyphal tips, the results suggest that peroxidases (LiP and MnP) are initially secreted at the apex of secondary growing hyphae and later slowly released into the surrounding medium.

Fungi↗
PubMed2004

Impact of altered gibberellin metabolism on biomass accumulation, lignin biosynthesis, and photosynthesis in transgenic tobacco plants.

Gibberellins (GAs) are involved in regulation of many aspects during plant development. To investigate the impact of altered GA levels on plant growth and metabolism, transgenic tobacco (Nicotiana tabacum) plants have been engineered to express either a GA20-oxidase (AtGA20-ox) or a GA2-oxidase (AtGA2-ox) gene from Arabidopsis under control of the cauliflower mosaic virus 35S promoter. Resulting plants were characterized by elongated or stunted shoot growth, respectively, indicating changes in the content of bioactive GAs. In accordance with the effect on plant growth, biomass production was increased or decreased in AtGA20-ox or AtGA2-ox plants, respectively, and was found to be positively correlated with the rate of photosynthesis as determined at the whole plant level. Differences in dry matter accumulation were most likely due to changes in lignin deposition as indicated by histochemical staining and quantitative measurements. Altered lignification of transgenic plants was paralleled by up- or down-regulation of the expression of lignin biosynthetic genes. Short-term GA3 feeding of excised petioles induced lignin formation in the absence of a transcriptional activation of pathway-specific genes. Thus, short-term GA treatment mediates lignin deposition most likely by polymerization of preformed monomers, whereas long-term effects on lignification involve elevated production of precursors by transcriptional stimulation of the biosynthetic pathway. Interestingly, analysis of stem cross sections revealed a differential effect of GA on the formation of xylem and pith cells. The number of lignified vessels was increased in AtGA20-ox plants pointing to a stimulation of xylem formation while the number of pith cells declined indicating a negative regulation.

Arabidopsis Proteins↗
PubMed1987

Shoot inversion inhibition of stem elongation in Pharbitis nil: a possible role for ethylene-induced glycoprotein and lignin.

Inversion of the upper shoot of Pharbitis nil results in the inhibition of elongation in the inverted stem. The objective of the present study was to determine how shoot inversion-induced gravity stress inhibited elongation and to elucidate the possible role of ethylene-induced glycoprotein and lignin in this process. Determinations of hydroxyproline, peroxidase, phenylalanine ammonia-lyase (PAL), phenol, and lignin content/activity were carried out by appropriate spectrophotometric methods. It was found that inversion and Ethrel treatments of upright shoots caused significant increases in hydroxyproline content, peroxidase, and PAL activity in 12 hours and in phenol and lignin contents in 24 hours. All of these increases except for that of cytoplasmic peroxidase activity were partially reversed by AgNO3, the ethylene action inhibitor. It is concluded that possible cross-linking associated with the accumulation of the ethylene-induced hydroxyproline-rich glycoprotein and lignin may be responsible for the later stages of cessation of elongation in the inverted Pharbitis shoot.

Cross-Linking Reagents↗
PubMed2006

Microbial community structure in soils with decomposing residues from plants with genetic modifications to lignin biosynthesis.

Lignin is a major determinant of the decomposition of plant materials in soils. Advances in transgenic technology have led to the possibility of modifying lignin to improve the pulping properties of plant materials for papermaking. Previous studies have shown that lignin modifications also affect the rate of plant material decay in soil. The aim of this work was to investigate short-term changes in soil microbial community structures when tobacco residues with reduced activity of enzymes in the monolignol pathway decompose. The residues from lignin-modified plants all decomposed faster than unmodified plant materials. The relative proportions of some of the structural groups of microbial phospholipid fatty acids were affected by genetic modifications, especially the proportion of double unsaturated chain fatty acids, indicative of fungi.

Alcohol Oxidoreductases↗
PubMed1991

Overproduction of lignin-degrading enzymes by an isolate of Phanerochaete chrysosporium.

Phanerochaete chrysosporium is a white rot fungus which secretes a family of lignin-degrading enzymes under nutrient limitation. PSBL-1 is a mutant of this organism that generates the ligninolytic system under nonlimiting conditions during primary metabolism. Lignin peroxidase, manganese peroxidase, and glyoxal oxidase activities for PSBL-1 under nonlimiting conditions were 4- to 10-fold higher than those of the wild type (WT) under nitrogen-limiting conditions. PSBL-1 was still in the log phase of growth while secreting the enzymes, whereas the WT had ceased to grow by this time. As in the WT, manganese(II) increased manganese peroxidase activity in the mutant. However, manganese also caused an increase in lignin peroxidase and glyoxal oxidase activities in PSBL-1. Addition of veratryl alcohol to the culture medium stimulated lignin peroxidase activity, inhibited glyoxal oxidase activity, and had little effect on manganese peroxidase activity in PSBL-1, as in the WT. Fast protein liquid chromatography (FPLC) analysis shows production of larger amounts of isozyme H2 in PSBL-1 than in the WT. These properties make PSBL-1 very useful for isolation of large amounts of all ligninolytic enzymes for biochemical study, and they open the possibility of scale-up production for pratical use.

Alcohol Oxidoreductases↗
PubMed1996

Identifying numerically abundant culturable bacteria from complex communities: an example from a lignin enrichment culture.

Culturable bacteria that were numerically important members of a marine enrichment community were identified and characterized phylogenetically. Selective and nonselective isolation methods were used to obtain 133 culturable bacterial isolates from model marine communities enriched with the high-molecular-weight (lignin-rich) fraction of pulp mill effluent. The culture collection was screened against community DNA from the lignin enrichments by whole-genome hybridization methods, and three marine bacterial isolates were identified as being numerically important in the communities. One isolate was in the alpha-subclass of Proteobacteria, and the other two were in the gamma-subclass of Proteobacteria. Isolate-specific 16S rRNA oligonucleotide probes designed to precisely quantify the isolates in the lignin enrichment communities indicated contributions ranging from 2 to 32% of enrichment DNA, values nearly identical to those originally obtained by the simpler whole-genome hybridization method. Two 16S rRNA sequences closely related to that of one of the isolates, although not identical, were amplified via PCR from the seawater sample originally used to inoculate the enrichment medium. Partial sequences of 14 other isolates revealed significant phylogenetic diversity and unusual sequences among the culturable lignin enrichment bacteria, with the Proteobacteria, Cytophaga-Flavobacterium, and gram-positive groups represented.

Bacteria↗
PubMed1999

Lignin-modifying enzymes of the white rot basidiomycete Ganoderma lucidum.

Ganoderma lucidum, a white rot basidiomycete widely distributed worldwide, was studied for the production of the lignin-modifying enzymes laccase, manganese-dependent peroxidase (MnP), and lignin peroxidase (LiP). Laccase levels observed in high-nitrogen (HN; 24 mM N) shaken cultures were much greater than those seen in low-nitrogen (2.4 mM N), malt extract, or wood-grown cultures and those reported for most other white rot fungi to date. Laccase production was readily seen in cultures grown with pine or poplar (100-mesh-size ground wood) as the sole carbon and energy source. Cultures containing both pine and poplar showed 5- to 10-fold-higher levels of laccase than cultures containing pine or poplar alone. Since syringyl units are structural components important in poplar lignin and other hardwoods but much less so in pine lignin and other softwoods, pine cultures were supplemented with syringic acid, and this resulted in laccase levels comparable to those seen in pine-plus-poplar cultures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of concentrated extracellular culture fluid from HN cultures showed two laccase activity bands (M(r) of 40,000 and 66, 000), whereas isoelectric focusing revealed five major laccase activity bands with estimated pIs of 3.0, 4.25, 4.5, 4.8, and 5.1. Low levels of MnP activity ( approximately 100 U/liter) were detected in poplar-grown cultures but not in cultures grown with pine, with pine plus syringic acid, or in HN medium. No LiP activity was seen in any of the media tested; however, probing the genomic DNA with the LiP cDNA (CLG4) from the white rot fungus Phanerochaete chrysosporium showed distinct hybridization bands suggesting the presence of lip-like sequences in G. lucidum.

Basidiomycota↗
PubMed1978

Ligninolytic enzyme system of Phanaerochaete chrysosporium: synthesized in the absence of lignin in response to nitrogen starvation.

The relationship between growth, nutrient nitrogen assimilation, and the appearance of ligninolytic activity was examined in stationary batch cultures of the wood-destroying hymenomycete Phanerochaete chrysosporium Burds. grown under conditions optimized for lignin metabolism. A reproducible sequence of events followed inoculation: 0 to 24 h, germination, linear growth, and depletion of nutrient nitrogen; 24 to 48 h, cessation of linear growth and derepression of ammonium permease activity (demonstrating nitrogen starvation); 72 to 96 h, appearance of ligninolytic activity (synthetic 14C-lignin leads to 14CO2). Experiments with cycloheximide demonstrated that appearance of ligninolytic activity occurs irrespective of the presence of lignin; lignin did not induce additional activity. Addition of NH4+ to cultures immediately prior to the time of appearance of the ligninolytic system delayed its appearance, suggesting that the NH4+ led to interference with synthesis of the enzyme system. Addition of NH4+ to ligninolytic cultures resulted in an eventual, temporary decrease in ligninolytic activity. The results suggest that all or essential protein components of the ligninolytic enzyme system are synthesized as part of a series of physiological ("secondary metabolic") events that are initiated by nutrient nitrogen starvation.

Basidiomycota↗
PubMed2004

Epidermal lignin deposition in quinoa cotyledons in response to UV-B radiations.

UV-B radiation (280-320 nm) is harmful to living organisms and has detrimental effects on plant growth, development and physiology. In this work we examined some mechanisms involved in plant responses to UV-B radiation. Seedlings of quinoa (Chenopodium quinoa Willd.) were exposed to variable numbers of UV-B radiation doses, and the effect on cotyledons was studied. We analyzed (1) cotyledons anatomy and chloroplasts ultrastructure; (2) peroxidase activity involved in the lignification processes; and (3) content of photosynthetic pigments, phenolic compounds and carbohydrates. Exposure to two UV-B doses induced an increase in the wall thickness of epidermal cells, which was associated with lignin deposition and higher activity of the peroxidase. The chloroplast ultrastructure showed an appearance typical of plants under shade conditions, likely in response to reduced light penetration into the mesophyll cells due to the screening effect of epidermal lignin deposition. Exposure to UV-B radiation also led to (1) enhancement in the level of phenolics, which may serve a protective function; (2) strong increase in the fructose content, a fact that might be related to higher requirement of erythrose-4P as a substrate for the synthesis of lignin and phenolics; and (3) reduction in the chlorophyll concentration, evidencing alteration in the photosynthetic system. We propose that the observed lignin deposition in epidermal tissues of quinoa is a resistance mechanism against UV-B radiation, which allows growing of this species in Andean highlands.

Cell Wall↗
PubMed1998

Predicting forage indigestible NDF from lignin concentration.

We used chemical composition and in vitro digestibility data from temperate and tropical forages to develop relationships between indices of lignification and forage indigestible NDF. Neutral detergent fiber indigestibility increased nonlinearly as the lignin concentration of the NDF increased. Differences in estimated indigestible NDF using equations developed for a specific forage class (C3 and C4 grasses and legumes) were small and are probably not biologically significant when compared to those estimated from a common equation. Selected equations were compared with the Cornell Net Carbohydrate and Protein System (CNCPS) for the prediction of ADG. The linear equation (2.4 times NDF lignin content) used by the CNCPS and the Beef NRC had some of the largest errors due to mean bias. A log-log model [4.37 x (lignin/NDF)(.84)] provided the best combination of low total prediction error, low mean bias, and minimal error due to regression bias when permanganate lignin was used. A similar equation based on sulfuric acid lignin [6.17 x (lignin/NDF)(.77)] also met the above criteria. These equations then were evaluated with the CNCPS model against animal growth data from diets ranging in forage quality. Regardless of the equation used for predicting unavailable fiber, the CNCPS underpredicted daily gain, with mean biases ranging from -.10 to -.22 kg/d. Regression bias ranged from .13 to .14 kg/d and the coefficients differed from unity (P = .0001). The new equations gave numerically lower energy allowable ADG by steers compared to the linear equation currently used by the CNCPS model. The estimates were lower due to a higher predicted indigestible NDF, which resulted in a lower estimated forage energy value.

Animal Feed↗
PubMedDate not supplied

Organ distribution and toxicity of lignin.

It is suggested that 125I-labeled natural and synthetic lignins administered orally to mice are absorbed through the digestive tract and excreted via urine, in addition to feces. Intravenous administration of lignins produced preferential accumulation of radioactivity in the liver and also in the stomach tissue and lung. It also induced an increase in the spleen weight (splenomegaly), suggesting that the immune system might be stimulated. Lignin significantly increased the heme oxygenase among several hepatic enzymes. Macroscopical examination of mice which were administered a lethal dose of lignin showed nasal and lung congestion leading to hemorrhage.

Absorption↗
PubMed1999

Reactions of blue and yellow fungal laccases with lignin model compounds.

Laccases of white-rot fungi Panus tigrinus, Phlebia radiata, and Phlebia tremellosa were isolated from cultures grown in liquid media which did not contain lignin and from the cultures grown on wheat straw. The physical and chemical properties of the laccases grown in submerged cultures were typical for blue fungal laccases. The laccases of the same fungi isolated from the solid-state cultures differed from the blue forms by lack of an absorption maximum at 610 nm. The typical blue laccases of P. tigrinus, Ph. radiata, and Ph. tremellosa acquired an ability to oxidize veratryl alcohol and a non-phenolic dimeric lignin model compound of beta-1-type only in the presence of a redox mediator, 2, 2'-azinobis(3-ethylbenzthiazolinesulfonic acid). The P. tigrinus and Ph. radiata yellow laccases catalyzed the oxidation of the same substrates without any mediator. The rate of the reaction of the blue laccases with a phenolic dimeric lignin model compound of beta-O-4-type was higher than that of the yellow laccases. The yellow laccases are apparently formed by the reaction of the blue laccases with low-molecular-weight lignin decomposition products.

Basidiomycota↗
PubMedDate not supplied

Effect of lignins on HIV-induced cytopathogenicity and myeloperoxidase activity in human myelogenous leukemic cell lines.

We have previously reported the potent stimulation effect of lignin on the iodination of myeloperoxidase (MPO)-positive cells. We investigated here the anti-HIV (human immunodeficiency virus) activity of lignins in the MPO-positive (HL-60) and -negative (U-937) human myelogenous leukemic cell lines. Natural lignified material and dehydrogenation polymers, but not their precursors, effectively inhibited the cytopathic effect of HIV infection in both these cells as well as in MT-4 and MOLT-4 cells. HIV infection caused significant reduction of MPO activity in HL-60 cells, regardless of the presence or absence of lignins. These data suggest that MPO might not be involved in the anti-HIV activity induction by lignins.

Antiviral Agents↗
PubMed1990

Structural characterization of the immunoactive and antiviral water-solubilized lignin in an extract of the culture medium of Lentinus edodes mycelia (LEM).

The active principle of EP3, a fraction from an extract of the culture medium of Lentinus edodes mycelia (LEM), which activates murine macrophages, causes proliferation of bone marrow cells, and inhibit the replication of Human Immunodeficiency Virus in vitro, was characterized as a water-solubilized lignin. The detailed structural feature of this water-solubilized lignin was investigated and shown to be a highly condensed and polycarboxylated lignin which is denatured and solubilized by Lentinus edodes from bagasse. The water-solubilized lignin itself was confirmed to have both immunological activities and the antiviral activity.

Animals↗
PubMedDate not supplied

[Effect of wood modification on lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus].

Lignin consumption and synthesis of lignolytic enzymes by the fungus Panus (Lentinus) tigrinus cultivated on solid phase (modified and unmodified birch and pine sawdusts) were studied. The fungus grew better and consumed more readily the birch lignin than the pine wood. Peroxidase activity was higher in the case of pine sawdust; laccase and lignolytic activities, in the case of birth sawdust. Treatment with ammonia or sulfuric acid decreased lignin consumption by the fungus cultivated on either medium. Modification of sawdust by ultrasound increased lignin consumption and may be recommended for accelerating biodegradation of lignocellulose substrates.

Ammonia↗